 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.texteditor;

 import java.util.ResourceBundle ;

 import org.eclipse.jface.text.source.IAnnotationModel;

 /**
  * Action for jumping to a particular annotation in the editor's text viewer.
  * <p>
  * This action only runs if <code>getTextEditor()</code>
  * implements {@link org.eclipse.ui.texteditor.ITextEditorExtension4}.</p>
  * <p>
  * This class may be instantiated; it is not intended to be subclassed.
  * </p>
  *
  * @since 3.2
  */
 public class GotoAnnotationAction extends TextEditorAction {

     /**
      * The navigation direction.
      * <code>true</code> to go to next and <code>false</code> to go to previous annotation.
      */
     private boolean fForward;

     /**
      * Creates a new action for the given text editor. The action configures its
      * visual representation from the given resource bundle.
      *
      * @param bundle the resource bundle
      * @param prefix a prefix to be prepended to the various resource keys
      * (described in <code>ResourceAction</code> constructor), or
      * <code>null</code> if none
      * @param editor the text editor
      * @param forward <code>true</code> to go to next and <code>false</code> to go to previous annotation
      * @see TextEditorAction#TextEditorAction(ResourceBundle, String, ITextEditor)
      */
     public GotoAnnotationAction(ResourceBundle bundle, String prefix, ITextEditor editor, boolean forward) {
         super(bundle, prefix, editor);
         fForward= forward;
         setHelpContextId(fForward ? IAbstractTextEditorHelpContextIds.GOTO_NEXT_ANNOTATION_ACTION : IAbstractTextEditorHelpContextIds.GOTO_PREVIOUS_ANNOTATION_ACTION);
     }
     
     /**
      * Creates a new action for the given text editor. The action configures its
      * visual representation from the given resource bundle.
      *
      * @param editor the text editor
      * @param forward <code>true</code> to go to next and <code>false</code> to go to previous annotation
      * @see TextEditorAction#TextEditorAction(ResourceBundle, String, ITextEditor)
      */
     public GotoAnnotationAction(ITextEditor editor, boolean forward) {
         this(EditorMessages.getBundleForConstructedKeys(), forward ? "Editor.GotoNextAnnotation." : "Editor.GotoPreviousAnnotation.", editor, forward); //$NON-NLS-1$ //$NON-NLS-2$
 }

     /*
      * @see org.eclipse.jface.action.IAction#run()
      * @since 3.2
      */
     public void run() {
         ITextEditor editor= getTextEditor();
         if (editor instanceof ITextEditorExtension4)
             ((ITextEditorExtension4)editor).gotoAnnotation(fForward);
     }
     
     /*
      * @see org.eclipse.ui.texteditor.TextEditorAction#setEditor(org.eclipse.ui.texteditor.ITextEditor)
      * @since 3.2
      */
     public void setEditor(ITextEditor editor) {
         super.setEditor(editor);
         update();
     }

     /*
      * @see org.eclipse.ui.texteditor.IUpdate#update()
      * @since 3.2
      */
     public void update() {
         ITextEditor editor= getTextEditor();
         if (!(editor instanceof AbstractTextEditor)) {
             setEnabled(false);
             return;
         }
         
         IAnnotationModel model= editor.getDocumentProvider().getAnnotationModel(editor.getEditorInput());
         setEnabled(model != null);
     }
 }

